White Water at North Pacific Beach
Unlike other regions that derive their humidity from summer rains, most moisture in the air in San Diego doesn’t come from rain at all. Instead, it’s carried in by the winds that sweep in from the coast.
Other regions along the Pacific Coast, such as the Gulf of California and even the Gulf of Mexico, have high rates of moisture. When ocean winds bring this moisture inland, it creates humidity, even if it hasn’t rained in San Diego itself. In fact, the occasional shower can break the humidity, so a light rainfall every few weeks isn’t as inconvenient as it may seem.
Offshore tropical storms can also lead to rising humidity rates in San Diego, so it’s a good idea to keep an eye on the tropical storms predictions in the Pacific off of Mexico when planning a visit. While it’s unlikely that any rain or high winds will reach the coast, these spikes in humidity can be uncomfortable if you’re not keeping cool at the beach or taking a dip in a hotel pool.
San Diego also features a few natural phenomenons that can actually reduce humidity levels in the air! For example, some wind conditions can cause upwelling, which brings the cooler water in the depths of the ocean up closer to the surface. As the ocean’s surface temperature cools, less moisture is released into the atmosphere, keeping the weather dry and thus the humidity at bay.